Abstract:

An exemplary optical lens group includes a first lens and a second lens.
The first lens comprises a first central portion and an annular stepped
portion. The annular stepped portion has a first outer step and a second
outer step. The first outer step has a first outer side surface and a
first downward-facing step surface. The second outer step has a second
outer side surface and a second downward-facing step surface. The second
lens comprises a second central portion and a peripheral portion. The
peripheral portion has an inner side surface. The first lens is engaged
in the second lens in a manner that the first outer side surface of the
first lens is in contact with the inner side surface of the second lens.
The second outer side surface of the first lens is spaced apart from the
inner side surface of the second lens.

Claims:

1. An optical lens group comprising:a first lens comprising a first
central portion and an annular stepped portion surrounding the first
central portion, the annular stepped portion having a first outer step
and a second outer step, the first outer step having a first outer side
surface and a first downward-facing step surface, the second outer step
having a second outer side surface and a second downward-facing step
surface;a second lens comprising a second central portion and a
peripheral portion surrounding the second central portion, the peripheral
portion having an inner side surface, the first lens engaged in the
second lens in a manner that the first outer side surface of the first
lens being in contact with the inner side surface of the second lens, the
second outer side surface of the first lens spaced apart from the inner
side surface of the second lens.

2. The optical lens group as claimed in claim 1, wherein the first outer
step and the second outer step are annular stages surrounding the first
central portion of the first lens therein.

3. The optical lens group as claimed in claim 1, wherein a gap is defined
between the first downward-facing step surface of the first lens and the
second lens.

4. The optical lens group as claimed in claim 1, wherein the first and
second outer steps taper in a direction toward the second lens.

5. The optical lens group as claimed in claim 4, wherein the first and
second outer steps have a same tapering degree.

6. The optical lens group as claimed in claim 1, further comprising a
spacer sandwiched between the first lens and the second lens.

7. The optical lens group as claimed in claim 1, wherein the first and
second lenses are comprised of plastic or glass.

8. A lens module comprising:a first lens comprising a first central
portion and an annular stepped portion surrounding the first central
portion, the annular stepped portion having a first outer step and a
second outer step, the first outer step having a first outer side surface
and a first downward-facing step surface, the second step having a second
outer side surface and a second downward-facing step surface;a second
lens comprising a second central portion and a peripheral portion
surrounding the second central portion, the peripheral portion having an
inner side surface, the first lens engaged in the second lens in a manner
that the first outer side surface of the first lens being in contact with
the inner side surface of the second lens, the second outer side surface
of the first lens spaced apart from the inner side surface of the second
lens;a spacer sandwiched between the second downward-facing step surface
of the first lens and the second lens; anda barrel receiving the first
lens and the second lens therein.

9. The lens module as claimed in claim 8, wherein the first outer step and
the second outer step are annular stages surrounding the first central
portion of the first lens therein.

10. The lens module as claimed in claim 8, wherein a gap is defined
between the first downward-facing step surface of the first lens and the
second lens.

11. The lens module as claimed in claim 8, wherein the first and second
outer steps taper in a direction toward the second lens.

12. The lens module as claimed in claim 11, wherein the first and second
outer steps have a same tapering degree.

13. The lens module as claimed in claim 8, wherein the first and second
lenses are comprised of plastic or glass.

[0003]The present invention relates to optical imaging devices and,
particularly, to an optical lens group and a lens module.

[0004]2. Description of Related Art

[0005]Currently, along with the development of electronic devices having
multiple functions, image pick-up apparatuses have become widely used in
a variety of consumer electronic devices, such as notebook computers,
personal digital assistants (PDAs), cellular telephones, etc. In the
meantime, demand for improving image quality is increasing, which
essentially depends on the quality of a lens module of the image pick-up
apparatus. That is, a lens module with high image quality is desired.

[0006]Referring to FIG. 4, an optical lens group 20 includes two lenses
24, 26. The lens 24 and lens 26 each has a central portion and a
peripheral portion. The peripheral portion of the lens 24 includes a
protuberance 242, and the peripheral portion of the lens 26 includes a
protuberance 262 coupled with the protuberance 242. The protuberance 242
has a surface 244 and the protuberance 262 has a surface 264. The two
surfaces 244, 264 are both incline planes and have the same gradient.
When assembling the two lenses 24 and 26, the surfaces 244 and 264
contact each other to fix the lens 24 with the lens 26. However, this
combination requires the surfaces 244 and 264 to be manufactured very
precisely. Furthermore, the friction force between the surface 244 and
the surface 264 may cause the deformation of the two lenses 24, 26. The
larger the contact area between the surface 244 and the surface 264 is,
the larger the friction force between the two lenses 24, 26 is. Due to
the friction force, the lens 24 may be inclined relative to the lens 26
after the lens 24 coupled to the lens 26. Therefore, the optical axis of
the lenses 24 and 26 may be not aligned to each other. Thus, images
generated by a lens module having the above optical lens group 20 may be
distorted, for example change in shape or fuzziness.

[0007]Therefore, a new optical lens group is desired to overcome the above
mentioned problems.

SUMMARY

[0008]An exemplary optical lens group includes a first lens and a second
lens. The first lens comprises a first central portion and an annular
stepped portion. The annular stepped portion has a first outer step and a
second outer step. The first outer step has a first outer side surface
and a first downward-facing step surface. The second outer step has a
second outer side surface and a second downward-facing step surface. The
second lens comprises a second central portion and a peripheral portion.
The peripheral portion has an inner side surface. The first lens is
engaged in the second lens in a manner that the first outer side surface
of the first lens is in contact with the inner side surface of the second
lens. The second outer side surface of the first lens is spaced apart
from the inner side surface of the second lens.

[0009]Other advantages and novel features of the present invention will
become more apparent from the following detailed description of present
embodiment when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]The components in the drawings are not necessarily drawn to scale,
the emphasis instead being placed upon clearly illustrating the
principles of the present embodiment. Moreover, in the drawings, like
reference numerals designate corresponding parts throughout the several
views.

[0011]FIG. 1 is an assembled, cross-sectional view of an optical lens
group according to an exemplary embodiment.

[0012]FIG. 2 is an enlarged view of an area II of the optical lens group
shown in FIG 1.

[0013]FIG. 3 is an assembled, cross-sectional view of a lens module
according to an exemplary embodiment.

[0014]FIG. 4 is a schematic, cross-sectional view of a typical optical
lens group.

[0015]Corresponding reference characters indicate corresponding parts. The
exemplifications set out herein illustrate at least one present
embodiment of the present lens module and optical module, in one form,
and such exemplifications are not to be construed as limiting the scope
of the invention in any manner.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016]Reference will now be made to the drawings to describe embodiments
of the present optical lens group in detail.

[0017]Referring to FIG. 1 to FIG. 2, an optical lens group 10 of an
exemplary embodiment is shown. The optical lens group 10 includes a first
lens 14 and a second lens 16. The first lens 14 and the second lens 16
can be made of plastic, glass or other optical materials known by person
skilled in the art.

[0018]The first lens 14 includes a first central portion 140 and an
annular stepped portion 141 surrounding the first central portion 140.
The first central portion 140 is configured for performing image
picking-up function. The annular stepped portion 141 has a first outer
step 142 and a second outer step 144. The first outer step 142 and the
second outer step 144 are annular stages surrounding the first central
portion 140 of the first lens 14 therein. The first outer step 142 has a
first side outer surface 146 and a first downward-facing step surface
145. The second outer step 144 has a second outer side surface 148 and a
second downward-facing step surface 147.

[0019]The second lens 16 includes a second central portion 160 and a
peripheral portion 161 surrounding the second central portion 160. The
second central portion 160 is configured for performing image picking-up
function. The peripheral portion 161 has an inner side surface 166.

[0020]The first lens 14 is engaged in the second lens 16 in a manner that
the first outer side surface 146 of the first lens 14 is in contact with
the inner side surface 166 of the second lens 16. The first and second
outer steps 142, 144 taper in a direction toward the second lens 16. In
the present embodiment, the first and second outer steps 142, 144 have a
same tapering degree.

[0021]The second outer side surface 148 of the first lens 14 is spaced
apart from the inner side surface 166 of the second lens 16. That is to
say, a gap is defined between the first downward-facing step surface 145
of the first lens 14 and the second lens 16. So the contact area of the
first lens 14 to the second lens 16 is reduced to reduce the friction
force between the two lenses. In addition, the friction force between the
second outer side surface 148 and the inner side surface 166 is
eliminated to easily/safely assemble the optical lens group 10. The
optical lens group 10 further includes a spacer 18 sandwiched between the
first lens 14 and the second lens 16 to adjust the distance between the
first lens 14 and the second lens 16.

[0022]In assembly, the first outer side surface 146 is guided by the inner
side surface 166. The first outer side surface 146 contacts the inner
side surface 166 to fix the first lens 14 to the second lens 16. Because
the second outer side surface 148 does not contact with the inner side
surface 166, the deformation of the two lenses 14, 16 caused by friction
is eliminated or reduced. Furthermore, the optical axis of the lenses 14
and 16 is coincident. Thus, a lens module having the optical lens group
10 can be more accurately assembled and have better photographic quality.

[0023]Referring to FIG. 3, a lens module 30 of an exemplary embodiment of
an environment utilizing the lens group 10 is shown. The lens module 30
includes a barrel 32. The barrel 32 is configured for receiving the
optical lens group 10. In this embodiment, the lens module 30 can be
installed into the electronic devices, such as notebook computers,
personal digital assistants (PDAs), or cell phones. Finally, it is to be
understood that the above-described embodiments are intended to
illustrate rather than limit the invention. Variations may be made to the
embodiments without departing from the spirit of the invention as
claimed. The above-described embodiments illustrate the scope of the
invention but do not restrict the scope of the invention.